Does Vitamin D Deficiency Cause Symptoms?

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

What are the symptoms of vitamin D deficiency?

Yes, deficiency of vitamin D can cause bone pain and muscle weakness.
However, mild vitamin D deficiency is not necessarily associated with any
symptoms. Vitamin D has been referred to as the "sunlight vitamin" because it is
made in our skin when we are exposed to sunlight. It can also be obtained
through dietary sources, but the main source of vitamin D in our diet is foods
that have been fortified to include the vitamin (such as in milk and other dairy
products). Vitamin D is only found naturally in significant levels in a few
foods, including fatty fish, cod-liver oil, and eggs.

Vitamin D acts to regulate the calcium and phosphate levels in the body, thus
promoting healthy bones. The characteristic vitamin D deficiency state is called
rickets. Rickets causes softening and poor mineralization of the bones, leading
to skeletal deformities. While rickets is the term typically used to describe
the condition in children, osteomalacia refers to the weakening of bones seen in
adults who are severely deficient in vitamin D.

The many roles of vitamin D in maintaining health and well-being are a
subject of active and ongoing research. Even subclinical (not producing signs or
symptoms) deficiencies in vitamin D have been linked to significant health
problems. Preliminary studies have shown that in addition to weakening of the
bones, vitamin D deficiency may be associated with conditions as varied as
cancers, asthma, cardiovascular disease, and autoimmune diseases.

Who is most likely to have vitamin D deficiency?

Those who have limited sun exposure are at risk for abnormally ow levels of
vitamin D, as are people who do not consume dietary sources of vitamin D,
particularly in combination with low sun exposure. Human milk and most infant
formulas have only very low levels of vitamin D. However, exposure to the sun is
not recommended as a source of vitamin D for infants and children due to the
long-term risks of skin cancer. The American Academy of Pediatrics recommends
vitamin D supplementation starting at 2 months of age for exclusively breastfed
infants.

People with kidney or
liver disease may have lower levels of vitamin D because these organs play a
vital role in creating the biologically active form of vitamin D in the body.

Those with dark skin may have a decreased ability to synthesize vitamin D in response to sunlight. The skin pigment melanin has been shown to inhibit the production of vitamin D by the skin.

People who are obese (have a BMI of 30 or greater) may have lower levels of vitamin D because fat cells extract vitamin D from the blood.

How do I know if I have vitamin D deficiency?

Vitamin D deficiency is currently underdiagnosed in the United States. Talk
to your health-care professional. If you are at risk of vitamin D deficiency, a
simple blood test can determine whether or not vitamin D deficiency is present.
This test is not recommended for everyone but is commonly used for people who
may have signs of weakened bones or who may have risk factors for vitamin D
deficiency.

Can vitamin D deficiency be treated?

Fortunately, vitamin D deficiency is easy to treat with a variety of
supplement preparations. Because abnormally high doses of vitamin D can be
toxic, it is important to discuss dosages of vitamin D with your health-care
professional, who can determine a course of vitamin D supplementation that is
best for you.